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Öğe Effect of Alkaloids on SARS-CoV-2(Malatya Turgut Özal Üniversitesi, 2020) Yılmaz Aydın, Duygu; Gürü, Metin; Gürü, SelahattinThe use of herbs in treatment has started with the history of humanity and a significant number of effective drugs are being developed from herbal sources. Primary and secondary metabolites, which are natural products produced by plants, are the most basic products of the industry directly or indirectly. One of these groups is alkaloids. Alkaloids show antiviral effects in viral diseases. COVID-19, which started in China and spread to many countries, has become an epidemic that threatens all humanity worldwide as a "Coronavirus Pandemic". No reliable and certified drug has yet been developed for this virus. Recent important research shows that plant-based substances can be potential candidates for developing effective and safe drugs against this virus. Referring to such recent studies, this study primarily shows that the antiviral potentials of some alkaloids especially quinine and artemisinin and its derivatives. In addition, the importance of antiviral plant substances in the development of a broad-spectrum drug for SARS-CoV-2 is emphasized.Öğe Enhancement of Heat Transfer Performance of a Heat Pipe by Using Calcium Magnesium Carbonate-Ethylene Glycol/Water Nanofluid with Sodium Dodecylbenzene Sulfonate(Budapest University of Technology and Economics, 2022) Yılmaz Aydın, Duygu; Gürü, Metin; Sözen, AdnanIn this paper, the effect of using CaMg(CO3)2/Ethylene Glycol-water (50:50%) as a working fluid on the thermal performance of thermosyphon heat pipe was experimentally studied. Nanofluid was prepared by two-step method using 2% concentration of CaMg(CO3)2 nanoparticle and 0.05% surfactant (Sodium dodecylbenzene sulfonate). For the experimental set-up, a straight copper pipe of one-meter length was used. The inner diameter of the pipe is 13 mm, and the outer diameter is 15 mm. Experiments were conducted at three different cooling water mass flow rates (5, 7.5, and 10 g/s) and different heating powers (200, 300, 400 W) to test heat pipe performance. It was observed that the CaMg(CO3)2 nanofluid reduced the average wall temperature of the heat pipe according to the base fluid. Furthermore, the efficiency and thermal resistance of the heat pipe were investigated separately for EG/water and CaMg(CO3)2 nanofluid. The maximum heat transfer enhancement was obtained as 9.55% under 400 W heating power and 10 g/s cooling water mass flow rate conditions and the maximum improvement in thermal resistance was observed as 21% at 200 W and 10 g/s cooling mass flow rate. Viscosity and specific heat of base fluid and CaMg(CO3)2 nanofluid were also determined and compared to each other.Öğe Fenol ve Bor Esaslı Çevre Dostu Pigmentin Deniz Araçlarında Boya Olarak Kullanılabilirliği(Gazi Üniversitesi, 2021) Olgun, Şeyma; Yılmaz Aydın, Duygu; Gürü, Metin; Ertürk, Aybüke AyşeTürkiye, etrafı denizlerle çevrili bir ülke olması sebebiyle deniz araçlarında kullanılan boyalar oldukça önemli hale gelmektedir. Cu2O2 içeren antifouling boyaların salınım sınırlamalarında kontrol gerekmektedir ve bakır içermeyen çevre dostu antifouling boyaların kullanımının zorunlu olacağı öngörülmektedir. Deniz araçlarında kullanılan antifouling boya pigmenti ilk olarak milli kaynaklardan sentezlenecek olup antifouling boya piyasasındaki ihtiyaç karşılanmış olacaktır. Bu çalışmada ilk olarak özel bor bileşiklerinden biri olan fenil floroborat sentez parametreleri belirlenerek daha sonra elde edilen pigmentin boyada kullanılabilirliği ve disk yöntemi ile antibakteriyel özelliği test edilmiştir. Yaş yöntem ile fenil floroborat sentezinde reaktant olarak fenol ve floroborik asit kullanılmış olup H2SO4 katalizör olarak tercih edilmiştir. Reaktant mol oranı ((nC6H5OH / nHBF4) = 1:1; 1,5:1; 2:1 ve 2,5: 1), sıcaklık (30 °C, 35 °C, 40 °C, 50 °C ve 60 °C) ve reaksiyon veriminde etkili reaksiyon süresi sentez parametreleri olarak incelenmiştir. Karakterizasyon çalışmaları için FT-IR ve BF4- iyon seçici elektrot kullanılmıştır. Fenil floroborat, reaktant mol oranı, sıcaklık ve reaksiyon süresi sırasıyla 2:1, 35 °C ve 90 dakika olduğunda % 62 verimle sentezlenmiştir. Pigment epoksi tür bağlayıcı ile solvent bazlı antifouling boya haline dönüştürülmüş olup deniz suyunda bekletildiğinde boya formunu korumuştur. Antibakteriyel aktivite, agar disk difüzyon yöntemi kullanılarak incelenmiş olup boya halindeki numunede difüzyondan kaynaklı antibakteriyel özellik görünmezken fenil floroborat pigmenti antibakteriyel özellik göstermiştir.Öğe The investigation of synthesis parameters, kinetic and flame retardant properties of magnesium fluoroborate(2021) Gürü, Metin; Güngör, Gülden; Yılmaz Aydın, Duygu; Çakanyıldırım, ÇetinIn this study, the synthesis parameters of magnesium fluoroborate, one of the special boron compounds, were determined and its flame retardant property in cotton fabric was investigated. In addition, kinetic studies were carried out to calculate the reaction order and activation energy. Magnesium fluoroborate was synthesized by wet method using magnesium carbonate and fluoroboric acid as reactants. The effects of reactant mole ratios (nMgCO3/nHBF4), temperature and reaction time on the reaction yield were investigated. FT-IR, XRD, TGA and BF4? ion selective electrode were used for characterization studies. Magnesium fluoroborate was synthesized with 98% yield when the mole ratio, temperature and reaction time are set as 1:3, 50 °C and 90 min, respectively. In addition, kinetic experiments reveal that the reaction obeys to first order kinetics and the activation energy was found as 6.75 kJ/mol. LOI test was used to determine the flame retardant property of synthesized magnesium fluoroborate. LOI test results proved that the magnesium fluoroborate has noteworthy flame-retardant property.Öğe Kalsiyum floroborat sentezi, kinetik ve alev geciktirici özelliklerinin belirlenmesi(TENMAK Bor Araştırma Enstitüsü, 2021) Yılmaz Aydın, Duygu; Güngör, Gülden; Gürü, Metin; Çakanyıldırım, ÇetinBu çalışmada özel bor bileşiklerinden olan kalsiyum floroboratın sentez parametreleri belirlenmiş ve pamuklu kumaştaki alev geciktirici özelliği incelenmiştir. Ayrıca kinetik çalışmalar yapılarak reaksiyon mertebesi ve aktivasyon enerjisi hesaplanmıştır. Kalsiyum floroborat, reaktant olarak kalsiyum oksit ve floroborik asit kullanılarak yaş yöntemle sentezlenmiştir. İncelenen parametreler; reaktant mol oranı (nCaO/nHBF4), sıcaklık ve reaksiyon süresidir. Karakterizasyon çalışmaları için FT-IR, XRD ve BF4- iyon seçici elektrot kullanılmıştır. Termal davranışın karakterize edilmesinde termogravimetrik-diferansiyel termal analiz (TG-DTA) kullanılmıştır. Kalsiyum floroborat, 1:4 reaktant mol oranı, 90?C sıcaklık ve 100 dakika reaksiyon süresinde %97 verimle sentezlenmiştir. Ayrıca yapılan kinetik çalışmada reaksiyonun birinci mertebeden olduğu belirlenmiş ve reaksiyonun aktivasyon enerjisi 19,14 kJ/mol olarak bulunmuştur. Sentezlenen kalsiyum floroboratın alev geciktirici özelliğini tespit etmek için LOI testinden yararlanılmıştır. Testler sonucunda kalsiyum floroboratın çok iyi alev geciktirici özellik gösterdiği gözlemlenmiştir.Öğe Nanofluids: preparation, stability, properties, and thermal performance in terms of thermo-hydraulic, thermodynamics and thermo-economic analysis(Springer, 2021) Yılmaz Aydın, Duygu; Gürü, MetinIn recent years, with the adaptation of nanotechnological engineering applications to complex systems, the use of nanofluids with better thermo-physical properties compared to conventional fluids has become widespread. In addition, studies on the preparation techniques of nanofluids, improving their thermal properties and evaluating their thermal performance are increasing. This study presents a review about preparation, evaluating and enhancement of the stability and thermal properties of nanofluids. Furthermore, the recent advances about the thermo-hydraulic, thermodynamic and thermo-economic performances of nanofluids in different types of thermal systems are summarized as well. The stability of nanofluid is a significant factor affecting its applicability. Various techniques have been used in the literature to enhance the stability of nanofluids such as surfactant addition, ultrasonic mixing and pH control. By using nanofluids, the desired thermo-physical properties can be obtained in order to improve the heat transfer property in the system. Some researchers recommend to hybrid nanofluids because of the hybrid effect of two or more particle types they contain. The reviewed literature also indicates that the use of nanofluids instead of conventional working fluids is an effective way to increase the thermo-hydraulic performance of thermal systems. In addition, according to the literature review, minimum entropy generation is an effective way to increase the energy efficiency and improve thermodynamic performance of the thermal system and the use of nanofluids provide a significant reduction in entropy production. © 2021, Akadémiai Kiadó, Budapest, Hungary.
